a) Field of the Invention
This invention relates to a motor damper that is arranged in a passage for cold air in a refrigerator and actuates a baffle using a motor as a driving source to control the cold air supply.
b) Description of the Related Art
A conventional motor damper is disclosed in, for example, Japanese patent laid open H6-109354 or U.S. Pat. No. 4,644,239.
FIGS. 13 and 14 show a damper 500, disclosed in the above mentioned Japanese patent H6-109354, comprising a baffle 52 for controlling the cold air supply and a driving mechanism 53 such as a motor which drives the baffle 52.
The baffle 52 is controlled by the driving mechanism 53 such that it swings with a journal 51 as a fulcrum and opens or closes a cold air gate 54 by contacting and retracting from it.
The motor damper 500 is arranged in a passage 67 for cold air in a refrigerator 60 as illustrated in FIG. 15, so that the cold air flows into the refrigerating chamber 62.
Also, FIGS. 16(a) and (b) illustrate a motor damper 500' disclosed in U.S. Pat. No. 4,644,239.
The damper 500' is comprised of a cam 57' which rotates integrally as the motor 53' spins, a pin 58' arranged eccentrically from the rotational center of the cam 57', and a wall 59' formed on the baffle 52', sandwiching the eccentric pin 58'. As the eccentric pin 58' contacts and retracts from the wall 59', the baffle 52' pivoting around the journal 51' converts the movement into a swinging movement at the cold air gate 54' for closing and opening the cold air gate 54'.
The conventional motor damper 500 opens/closes the baffle 52 pivoting around the journal, so it does not open up to a position parallel to the cold air flow in the passage 57. As FIG. 15 shows, the slanted position becomes the position to open the cold air gate 54, and opens no further.
In the same manner, in the conventional motor damper 500', a distance between the journal 51' of the baffle 52' and the eccentric pin 58' is so long and the rotational distance of the eccentric pin 58' is so short that the baffle 52' does not swing very much.
For this reason, in the conventional motor damper 500 and 500', the baffle 52 and 52' resists the flow of cold air, thus providing the inefficient structure for prompt diffusion of the cold air.
In order to swing the baffle 52 over a large distance in the damper 500 illustrated in FIGS. 13 and 14, the rotational distance of the rack of the driving mechanism 53 needs to be long.
Also, in the damper 500' illustrated in FIG. 16, the moving distance of the eccentric pin 58' needs to be long. Thus, both dampers 500 and 500' are large.
In addition, due to the above mentioned structure as illustrated in FIG. 15, the inward projection width M of the refrigerator 60 is naturally large, thus providing a factor which reduces the capacity of the refrigerator 60.